Idaho State Highway 75 - Route Description

Route Description

State Highway 75 begins at a junction with US-93 on Greenwood Street in Shoshone at an elevation of just under 4,000 feet (1,220 m) above sea level. The highway heads northward, and ascends the Big Wood River valley, into Blaine County, past the Magic Reservoir to the west and crosses US-20 at Timmerman Junction at 4,884 feet (1,489 m).

It continues northward as the Sawtooth Scenic Byway to pass through the Big Wood River communities of Bellevue, Hailey, and Ketchum. Sun Valley is accessible via a spur route junction in Ketchum at Third Street, which becomes Sun Valley Road.

Seven miles (11 km) north of Ketchum, the highway passes by the headquarters of the Sawtooth National Recreation Area at 6,250 feet (1,905 m) and the Boulder Mountains to the north, with peaks over 11,000 feet (3,350 m). SH-75 climbs past the Galena Lodge to the Galena Summit at 8,701 feet (2,652 m), then descends to the scenic viewpoint about a mile later, which overlooks the Sawtooth Mountains to the west and headwaters of the Salmon River in the Sawtooth Valley.

Highway 75 descends the grade and reaches the upper end of the valley floor at new Sawtooth City at 7,190 feet (2,192 m), and then enters Custer County. It runs northward down the valley with the Salmon River to Obsidian and Stanley, with the Sawtooths to the immediate west and the White Cloud Mountains to the slightly more distant east. The turnoff to picturesque Redfish Lake is about five miles (8 km) south of Stanley.

At Stanley, the highway intersects with the northern terminus of State Highway 21, the Ponderosa Pine Scenic Byway from Boise, through Idaho City and Lowman. Highway 75 becomes the Salmon River Scenic Byway, and continues north for a mile, then veers east with the twisty river towards Clayton, then north towards Challis, where the route terminates and rejoins US-93 just south of the city limits.